URBANA, Ill. (U.S.A.) — If you’re a crayfish, location is everything. Here in North America, times are tough for the mini crustaceans. Habitat destruction, damming, and pollution have decimated local populations, such that many species are in dire need of help. But when some of the same species were exported to Europe, they found a much more favorable environment and are thriving. A little too much — American expats bully European crayfish and spread disease, driving many local species to the brink.

Conservation scientists and those who coordinate invasive species control efforts have different aims, but both need one thing: to know where their target crayfish are. Previously, researchers and conservation planners had to spend hours sifting through separate data sources to learn where target species had been documented, but a new mapping project led by the West University of Timișoara, Romania (WUT) and the University of Illinois Urbana-Champaign puts 427 crayfish taxa and over 100,000 observation records on the first searchable global atlas: World of Crayfish.

The free-to-access crayfish atlas is described in Peer J.

“One of the most basic pieces of information to know about a species is where it lives: its distribution and its range size. But we just don’t have that information for a lot of crayfish species,” said atlas co-creator Caitlin Bloomer, teaching assistant professor in the Department of Natural Resources and Environmental Sciences, part of the College of Agricultural, Consumer and Environmental Sciences at Illinois. “About a third of crayfish are thought to be threatened or endangered, but for another 20-ish percent, we don't have the data available to even assess what their conservation status should be.”

Bloomer admits most people outside her field don’t particularly notice or appreciate crayfish, but she says they’re surprisingly charismatic little creatures and are extremely important in their freshwater ecosystems. Considered “keystone species” by many, crayfish play an outsized role as food sources for other animals and as ecosystem engineers, creating burrows that act as habitat for many species in semi-terrestrial environments. Unfortunately, their impacts as invaders are just as significant.

“Invasive species are one of the gravest challenges to biodiversity in Europe, with profound ecological, economic, and societal consequences. They disrupt ecosystems, outcompete native species, and impose significant costs on sectors like agriculture and fisheries. In some cases, they even threaten public health,” said atlas co-creator Mihaela Ion, researcher at the Institute of Biology Bucharest, Romanian Academy. “A unified, science-driven approach is essential to mitigate their impact.”

These ecosystem changes happen on a local scale, of course, but crayfish conservation and invasion mitigation have become bigger-picture challenges, often requiring transnational coordination. That’s why Ion, Bloomer, and their collaborators think the new global crayfish atlas will make a difference.

“We're looking at climate change, habitat loss, and international spread of invasive species and disease,” Bloomer said. “These global issues require global collaborations to move forward and make an impact.”

Lucian Pârvulescu, professor at WUT and project coordinator for the atlas said, “The World of Crayfish™ (WoC) platform is designed to become a transformative tool in biodiversity research and management. It serves as a foundation for integrating expert-validated datasets and applying advanced analysis techniques to address pressing ecological challenges like invasive species management. WoC exemplifies the future of biodiversity data infrastructure — accessible, integrative, and purpose-driven. By focusing on freshwater ecosystems, particularly crayfish species, it addresses an urgent need for tools that do more than collect data — they provide solutions.”

Creating the atlas meant pulling the GPS coordinates from every modern crayfish occurrence record in the literature and from museum and agency collections. Several thousand records were sourced on-campus from the Crustacean Collection of the Illinois Natural History Survey, part of the Prairie Research Institute at Illinois. Atlas co-creator and emeritus curator Christopher Taylor has collected and curated the collection for nearly 30 years.

The more-than-100,000 data points can be visualized on a world map scalable to 20-kilometer hexagons, including an address lookup tool. Bloomer says this spatial scale is meaningful for conservation planning efforts but masks the exact locations where sensitive or imperiled species were found. Researchers and resource managers can register for an account with the website where they can access more detailed location data.

Future updates to the atlas will make it even more powerful.

“Through collaboration with international experts and leveraging scientific advancements, WoC aims to combine ecological data with geospatial and predictive tools. These tools will support tailored analyses, such as mapping invasive species dynamics, evaluating habitat suitability, and predicting population trends,” Pârvulescu said. “The platform’s strength lies in its ability to merge diverse data streams into a cohesive system that generates actionable insights.”

Ultimately, the team hopes the atlas will empower researchers, policymakers, and agencies to develop conservation assessments and policies to protect these important animals with precision and urgency. But Bloomer also hopes the atlas will inspire members of the public to get curious about crayfish.

“The unfortunate reality in conservation biology is that a lot of the species that get attention and funding are charismatic megafauna that people see on TV or in zoos,” she said. “This website gives the public better access to information on what lives near them, and could get them more interested in their local landscape. Hopefully, they’ll see that crayfish are just as cool as lions and rhinos.”

The study, “World of Crayfish™: a web platform towards real-time global mapping of freshwater crayfish and their pathogens,” is published in Peer J [DOI: 10.7717/peerj.18229]. Ion and Bloomer co-led the paper along with 89 additional crayfish and IT experts around the world. The work was supported by (1) the West University of Timisoara through the U InnoVaTe programme, via an UIVT Mature grant awarded to the World of Crayfish (WoC1.0)” project in May 2023, and (2) the Ministry of Research, Innovation and Digitization, CNCS/CCCDI–UEFISCDI, within the PNCDI III programme (No. PN-III-P4-ID-PCE-2020-1187).

Bloomer is also affiliated with the Illinois Natural History Survey.